Electromagnetic device



NOV. 14, 1939. M|HAEL|$ 2,180,159

ELECTROMAGNETI C DEVICE Filed Aug. 12, 1938 inventor Z Loflhar" Mich elis, by Hi8 ACt orneg.

Patented Nov. 14, 1939 2,180,159 ELECTROMAGNETIC DEV ICE Lothar Michaelis, Washington, D. 0., assigfior to General Electric Company, a corporation of New York Application August 12, 1938, Serial No. 224,535

13 Claims.

This invention relates to electromagnetic devices and particularly to electromagnetic devices with a core comprising magnetic material and having uni-directional current conducting properties.

An object of the invention is to provide the core of an electromagnetic device with at least one layer of magnetic material and at least one layer of a second material which cooperates with the layer or layers of magnetic material to form a uni-directional conductor, in particular a rectifier.

Another object of the invention is the provision of a simple and compact arrangement of an electromagnetic device in which the core of magnetic 10 material forms at least part of a rectifier.

Still another object of the invention is the provision of an electromagnetic device in which the magnetic material of the core is used both for carrying the magnetic flux and for forming at least one of the elements of a contact rectifier.

A further object of the invention is the provision of an electromagnetic device for an alternating current circuit in which the magnetic core is so arranged and composed that it generates a uni-directional magnetic flux.

Other objects and advantages of the invention planes.

iron and selenium but other rectifiers containing will be apparent from the specification and drawing in which are illustrated and described several of various possible embodiments of the invention. In Fig. l the invention is embodied in an alternating current transformer for supplying direct current to an operating winding of a switch;

Fig. 2 is a modification in which the electromagnetic device of the invention is included in an electric circuit and is also used as a rectifier in another circuit;

Figs. 3 and 4 show relays built in accordance with the invention; and

Fig. 5 is a modification in which the principles of the invention are applied to the core of a time delay relay.

It is well known that a cell comprising layers of iron and selenium in contact with each other has uni-directional current conducting characteristics and may be used as a rectifier or as a photo electric cell. Such characteristics are obtained by an asymmetrical arrangement of the three parts constituting the cell, namely, the two electrodes and the rectifying substance as described,

for example, in the Presser Patent 1,778,645 and known to those skilled in the art. According to my invention, cells in which at least one layer has magnetic properties are used for building up the magnetic circuit of electromagnetic devices. The term "electromagnetic device as used at least one magnetic material such as nickel and tellurium or iron-iron oxide may be employed.,1

The term magnetic contact type rectifier as used in this specification is intended to include any contact type rectifier in which a magnetic material is employed as one of the constituent active parts of the rectifier. 20'

Referring to Fig. 1 ll designates a magnetic core of a transformer constructed according to the invention. This core may be composed of layers of iron A, layers of selenium B, and layers of nickel C. The core is provided with a primary 25 winding l2 and a secondary winding 13. The primary winding is connected through a switch l8 to a ource of alternating current I0. Located on opp site sides of the rectifier laminations are two terminals l4 and I5. The secondary winding 30 I3 on the core H is insulated therefrom and has one of its ends connected to terminal l4 and the other end to terminal IS. A load, for example a solenoid ll, is connected'between terminals l5 and IS. The secondary circuit thus includes the 35 secondary winding l3, the core H of the transformer acting as a rectifier and the load ll. In operation, "when ,the primary winding is energized with alternating current by closing the switch l8, an alternating current voltage is in- 40 duced in the secondary winding [3 but the magnetic core H acting as a rectifier in series with the load allows current to pass through it in only one direction. g a

While in Fig. 1 the rectifier is electrically in- ,5

cluded in the secondary circuit of the transformer, this is not always necessary. The rectifier core might for instance be included in any independent circuit where rectification is necessary in' which case the transformer secondary would 50 be connected in the usual way to an alternating current load. An arrangement illustrating such a modification of the invention is shown in Fig. 2.

In the arrangement of Fig. 2 a condenser I8 is connected through a rectifier I! and a switch 20 which is connected in se to an alternating current source of supply l0. Connected across the condenser I6 is operating coil 2| of an electromagnetic device 22 such as a relay, the circuit also including a switch 23. The rectifier I9 comprises layers of magnetic material and forms wholly or in part the magnetic core of the electromagnetic device.

When switch 23 is open and switch 20 is closed, the condenser is charged from the source i0. As soon as the condenser is fully charged, current no longer passes through the rectifier i9. Switch 20 may now be opened and switch 23 closed thereby causing a discharge of the condenser through the coil 2| of the electromagnetic device.

It is evident from'the foregoing description of Figs. 1 and 2 that the same core (Fig. l) or 19 (Fig. 2) may be made to actlooth as a rectifier and as a magnetic core of an electromagnetic device in the same or in an independent circuit.

In the modification shown in Fig. 3, the invention is incorporated in a relay, The core desigr nated by numeral 24 is formed of layers of iron and selenium in the manner described in com nection with Fig. l. The relay coil is shown at 25 and the armature at 26. The rectifier terminals 21 and 28 are connected to one side of an alternating current source ill and the winding 25 respectively. The other terminal 29 of winding 25 is connected in series circuit relation with the switch 30 to the other side of the source oi supply Ill. The relay controls circuit 3i through contacts 32.

' The operating circuit for exciting the relay may be traced from one side of the alternating current supply source it through push button switch 36, operating coil 25, terminal 28, rectifying core 24, terminal 2'11 to the other side of the source of supply. By virtue of the rectifying action of the core 24 current is allowed to fiow through the coil 25 in only one direction thus causing a unidirectional fiux to act on the armature it. It will be noted from the drawing that the electric current passing through the relay core as a rectifier is in a direction perpendicular to the plane of the laminations, while the main axis of the relay coil is in the direction of the laminations. The field produced by the current as it passes through the rectifier and the field produced by the current passing through the relay 'coil are at right angles to each other so that they do not influence each other. Furthermore, the magnetization of the individual magnetic layers due to the current passing through the core is small as compared with the magnetization caused by the surrounding exciting coil.

In the modification shown in Fig. 4, the movable armature 33 constitutes the rectifier and may be composed of a layer of iron A, a layer of selenium B, and a layer of tin D. The rectifier portion of the armature is provided on opposite sides with terminals 34 and 35. The core 36 is provided with an exciting coil 371 which is connected to an alternatin current source of supply ID in series circuit relati n with the armature 35: To allow freedom of movement of the armature, the terminals 34 and 35 are connected through flexible wires 38 and 39 to the coil and the source of supply respectively.

An operating circuit may be traced from one side of the alternating current source [Ill through push button switch 3d, coil 37, flexible wire 3%,

terminal 34, armature 33, terminal and flexible wire 89 to the other side of the source of supply. Since the 'arma'ture 33 forms a rectifier ir' uitrelation with the operating coil 31, the latter will be energized with a pulsating direct current thereby providing a uni-directional flux in the core 36 and the iron layer or the armature 33. By closing switch 40, the iron layer A of the armature 33 is attracted to the core 36 thereby closing contacts 4|.

In Fig. I have disclosed a slow acting relay according to the invention. The core 42 of the relay is composed of layers of magnetic material and layers of selenium or other material which, together with the layer of magnetic material, forms a rectifier, Connected to the terminals 43 and 44 of the rectifier is a winding 45. The energizing winding 46 is connected to the source of supply 41 which is shown as a storage battery. A switch 46 is inserted in the circuit of the winding 46. The armature of the relay controls circuit 49 through contacts 50.

On closing switch 48 a flux is set up by the coil 46 in the magnetic material of the core 42 which induces a voltage in the winding 45. A similar voltage but of opposite polarity is induced in winding 45 when switch 48 is opened and the field of coil 46 begins to die away. Depending on the relative connection between the coil 45 and the rectifier, the voltage induced in winding 45 will cause a current to fiow in one direction but not in the opposite direction with. the result that the operation of the relay may be delayed either on closing or on opening.

Although I have assumed in the description of Figs. 1, 3 and 5 that the rectifier is built of layers of iron, selenium and nickel, it is possible to use other combinations to, obtain a magnetic contact type rectifier. In particular, iron layers may be used which have different degrees of contact with opposite sides of the selenium layer. Also, ironiron oxide rectifiers may be advantageously used, Various methods of building rectifiers in this manner are well known in the art and the rectifier per se is not the subject of my invention. Similarly, other rectifiers comprising magnetic material may be substituted for the iron, selenium and tin cell of Fig. 4. This arrangement is of particular use in connection with light sensitive arrangements wherein it is desirable to have the armature form the light sensitive element.

In the various arrangements the iron-selenium elements or similar elements containing other magnetic materials may be used to form only part of the magnetic circuit and additional magnetic material may be used for the construction of the core of the electromagnetic device. The number of rectifying elements which are included in the electric circuit depends upon the voltage and current conditions and if necessary, several layers of the electromagnetic device may be electrically connected in parallel. Instead of connecting the magnetic rectifiers in series with the apparatus to be operated, parallel connections may in some instances be preferable.

The broad idea of my invention is the use of the magnetic materialin a magnetic contact type rectifier for rectification and for carrying the magnetic fiux in an electromagnetic device. In other words, the active magnetic material of an electrical device is used at the same time for obtaining a rectifying efiect in an electric circuit.

While I have disclosed and illustrated in detail various embodiments of my invention, it will, of course, be understood that I do not wish to be limited thereto, since many modifications may be made both in the circuit arrangements shown to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electromagnetic device comprising a magnetic circuit, an insulated coil interlinked therewith, and a magnetic contact type rectifier formed at least in part by material comprised in said magnetic circuit.

2. The combination of a magnetic contact type rectifier and a coil for producing a flux in the magnetic material of said rectifier.

3. In an electromagnetic device, a winding and a core therefor composed at least in part of magnetic material, said magnetic material forming one of the operative elements of a contact type I rectifier.

4. Electromagnetic apparatus having in combination a rectifier with layers of magnetic material and a coil surrounding said rectifier, said coil being arranged in such a way that its flux is perpendicular to the direction of the current flow through said rectifier.

5. In an electromagnetic device having in combination a direct current winding and an iron core, said iron core forming part of a magnetic contact type rectifier connected in circuit with said direct current winding.

6. An electromagnet for alternating current having in combination a magnetic contact type rectifier and a direct current winding surrounding said rectifier.

7. An electric device comprising a magnetic core and an exciting winding, an electric circuit connected to said winding, said core including a magnetic contact type rectifier, and a second electric. circuit connected to said rectifier.

8. A device for converting alternating current into direct current comprising an alternating current winding, a core, and a direct current winding, said core including the operative elements of a rectifier and being connected to said direct current winding.

9. An electric device for direct current, a source of alternating current, a transformer connected between said source and said device, and a rectifier in circuit with said device, said rectifier forming at least part of the magnetic circuit of said transformer.

10. A control circuit for 'a direct current switch having an operating winding, comprising a source of alternating current, a transformer having a magnetic core and primary and secondary windings, a control switch for connecting said primary winding to said source, said secondary winding being connected to said operating winding,

and rectifying means in circuit with said secondary winding and said operating winding, said rectifying means forming at least part of the magnetic circuit of said transformer.

11. An electromagnetic device having primary and secondary windings and a magnetic core, said magnetic. core forming part of a magnetic contact type rectifier.

12. In an electromagnetic relay, a core comprising magnetic material, and a winding for exciting said core, the magnetic material of said core comprising at least one of the electrodes 01' a contact type rectifier and connected in circuit with said exciting winding.

13. In an electric circuit, a condenser, a circuit 'for charging said condenser including a magnetic contact type rectifier, a discharge circuit connected to said condenser including a. coil and a magnetic core, said rectifier forming at least part of said magnetic core.

LOTHAR moms. 

